| Scotole Limited | Wholesale & retail | 2025 |
| Scott Racing Motorcycles Ltd | Manufacturing | 2011 |
| Scotts Fine Foods Ltd | Manufacturing | 2014 |
| Scotts Fruit & VEG Ltd | Wholesale & retail | 2026 |
| Sctni Limited | Education | 2015 |
| SCW Technologies Limited | Professional & scientific | 2018 |
| Sea-Lution CIC | Health & social care | 2025 |
| Seapark Mews Management Company Ltd | Households | 2026 |
| Secure UR Property Limited | Administrative & support | 2012 |
| Sedar 24 Ltd | Real estate | 2024 |
| Sedar Limited | Wholesale & retail | 2002 |
| Serj Investments Limited | Real estate | 2021 |
| SFC26 Property Ltd | Real estate | 2021 |
| Sfjassociates Ltd | Professional & scientific | 2023 |
| Shack Dogs Surf School Ltd | Wholesale & retail | 2021 |
| Shanvey Ltd | Construction | 2024 |
| Shelton Meadow Management Company Limited | Households | 2002 |
| Sheneard Management Ltd | Households | 2020 |
| Shergrim Grove Management Limited | Households | 2006 |
| Showbin Limited | Wholesale & retail | 2024 |
| Sidings (Enniskillen) Management Company Limited - the | Households | 2005 |
| Sign-It Designs Limited | Manufacturing | 2008 |
| Simohen Limited | Real estate | 2024 |
| Simply Tech Solutions Limited | Information & communication | 2014 |
| Simpson Developments Ltd | Construction | 1996 |
| Siren Advisory Services (NI) Limited | Professional & scientific | 2013 |
| Siren Associates Limited | Professional & scientific | 2015 |
| Siren Consulting (NI) Limited | Professional & scientific | 2016 |
| SJR Partnership Ltd | Real estate | 2024 |
| Skerries Enterprises Limited | Hospitality | 2024 |
| Skyline Windowsni Ltd | Manufacturing | 2012 |
| Slemish Enterprises Limited | Wholesale & retail | 2004 |
| Smith's Facilities Group Ltd | Administrative & support | 2024 |
| Smyth Steel Limited | Manufacturing | 1980 |
| Smyths Finance Limited | Financial services | 2023 |
| Snapzon Ltd | Wholesale & retail | 2025 |
| Solobook Travel Limited | Administrative & support | 2023 |
| Solvanna Limited | Administrative & support | 2025 |
| Somerset Agencies Ltd | Wholesale & retail | 2019 |
| Sourhill Road Management Company Ltd | Households | 2006 |
| South Pier Management Company Limited | Households | 2016 |
| Spacecraft Property Limited | Construction | 2004 |
| Spaces by Liminal Ltd | Professional & scientific | 2022 |
| Spatialest Ltd | Information & communication | 1997 |
| SPE 23 Limited | Financial services | 2023 |
| SPE 25 Limited | Other services | 2020 |
| SPE 26 Limited | Extraterritorial | 2025 |
| SPE 27 Limited | Extraterritorial | 2025 |
| SPE 28 Limited | Real estate | 2025 |
| SPE 29 Limited | Real estate | 2025 |
| Specific Training Limited | Education | 2010 |
| Spittal Hill Estate Limited | Professional & scientific | 2021 |
| Springvalley Farms Limited | Agriculture & fishing | 2016 |
| Sprucefield Bioenergy Ltd | Energy | 2026 |
| SRH Meris Ltd | Health & social care | 2019 |
| ST. James's Park Management Limited | Households | 2003 |
| Stackweaver Limited | Information & communication | 2026 |
| Station Park (Drumgoon) Management Limited | Households | 2014 |
| Stavri Consulting Limited | Information & communication | 2011 |
| Steel Harpy Gaming Limited | Wholesale & retail | 2025 |
| Stephen Rainey Limited | Health & social care | 2016 |
| Stevensons Kilrea (Holdings) Limited | Financial services | 2021 |
| Stevensons Kilrea Limited | Wholesale & retail | 2020 |
| Stimulus Learning Ltd | Professional & scientific | 2023 |
| Stockholm House Management Limited | Households | 1993 |
| Stone Capital Ltd | Real estate | 2017 |
| Stonebridge Manor Management Company Ltd | Households | 2018 |
| Strand Apartments Management Company Limited | Households | 1992 |
| Strand Court Management Services Limited | Households | 2000 |
| Strand Estates N.I. Limited | Extraterritorial | 2009 |
| Strand Fashions Limited | Wholesale & retail | 2012 |
| Strand Holdings Limited | Hospitality | 2018 |
| Strand Hotel Hiex Derry/Londonderry Ltd | Hospitality | 2012 |
| Strand Hotels Derry Limited | Hospitality | 2018 |
| Strand Place Management Company Limited | Extraterritorial | 2016 |
| Strand Road Golf Limited | Arts & recreation | 2023 |
| Strand Road Services Ltd | Construction | 2021 |
| Strandmore Management Company Limited | Households | 2021 |
| Strandview Apartments Management Company Limited | Households | 2003 |
| Streamline Drainage Ltd | Professional & scientific | 2019 |
| Streamlined Sheets Limited | Wholesale & retail | 2025 |
| Strength 28 Limited | Wholesale & retail | 2020 |
| Strollers Pram and Nursery Limited | Wholesale & retail | 2024 |
| Student and Holiday Lettings Ltd | Hospitality | 2019 |
| Student Lettings Management Ltd | Real estate | 2020 |
| Studio Myco Ltd | Professional & scientific | 2023 |
| Studio Rogers Limited | Construction | 2000 |
| Studio Voodoo Ltd | Information & communication | 2024 |
| Stunt Double Music Ltd | Arts & recreation | 2021 |
| Success at Work Ltd | Professional & scientific | 2021 |
| Summerfield Mews Management Company Limited | Households | 2001 |
| Sunset Management Company Limited | Professional & scientific | 2014 |
| Surefoot Scaffolding Limited | Construction | 2018 |
| Surf Shack - Castlerock Ltd | Wholesale & retail | 2020 |
| Swilly Park Management Limited | Households | 2009 |
| Switch Electrics (Maghera) Ltd | Construction | 2016 |
| SXS Bushmills Limited | Real estate | 2024 |
| Sydney B Scott Ltd | Wholesale & retail | 2012 |
| T a Electric Company Ltd | Construction | 2003 |
| Tanuj Chopra Agencies (N.I.) Ltd | Wholesale & retail | 2021 |